1. Lucerne growing in pots was defoliated once or at intervals of 3 weeks to either 1 or 5 in. Both height and frequency of cutting affected growth of tops and roots significantly; analysis of root weights also showed that these treatments had interacted. Cumulative yield of tops and leaf area per plant were linearly related.

The grazing behaviour of village cattle in the Eastern Province of Zambia (Northern Rhodesia) was studied.

Usually, the cattle graze in the bush during the rains and on the dambos in the dry season. Where most of the upland was cultivated, the cattle were forced to graze in the dambos during the rains contrary to correct land use. The arable land and crop residues are grazed after the harvest in middry season.

Ammonium sulphate alone and treated with the nitrification inhibitor 2-chloro-6-(trichloromethyl)- pyridine, at rates equivalent to 1 and 2% of the weight of N applied, was applied to sandy- and clay-loam soils. Ammonium sulphate was given in November 1962, and soil samples, taken in spring 1963, down to 36 in. on the sandy-loam and 18 in. on the clay-loam, were analysed. When the ammonium sulphate was broadcast on the soil surface, 2% of the inhibitor, inhibited nitrification of the ammonium-N more than 1%, but when it was placed in the soil both rates were equally effective.

1. An experiment is described in which the partition of calcium phosphorus, sodium, potassium and manganese in the excreta of the colostomized laying hen fed a diet adequate in these minerals is examined.

1. During the winter of 1956-57, three levels of indoor feeding, high, mid, and low, were imposed on groups of North and South Country Cheviot ewe hoggs (sheep between 6 months and 1½ years) born 1956. During the winter of 1957-58, only two levels, high and mid, were fed indoors to groups of hoggs born 1957, with the low level being represented by hill wintering. After 12 months of age in each year, all were grazed together on the same hill pasture.

The effect of nitrogenous fertlizers on the watersoluble carbohydrate content of pure grass swards has been studied in three experiments.

Leys that lasted 3½ years, including grass/white clover, grass alone, white clover alone, lucerne alone, and lucerne/cocksfoot, and also including leys managed for seed production, were followed by two successive crops of winter wheat and then by marrow-stem kale. The first wheat crop that followed grazed leys of white clover, lucerne, or lucerne/cocksfoot yielded 32 cwt. of grain (dry matter)/acre, after cocksfoot or timothy/red clover seed-production leys the yield was 21 cwt./acre. The corresponding weights of N in the wheat were 105 and 57 lb./acre.

1. The effect of rest during the autumn and winter on the dry-matter production and botanical composition of a cattle-grazed pasture was studied for four consecutive seasons.

1. The suitability of three ratios of sorghum grain to sorghum silage (40:60, 60:40, and 80:20) with and without a supplement of 60 g. urea per head per day for the finishing of cattle in yards was examined.

1. In a 3 x 3 x 3 factorial experiment of two replications, with three-factor interactions partly confounded with block effects, the effects of lucerne variety (du Puits or one of two Institute synthetics), tall fescue variety (S.170 or one of two Institute bulks) and spacing (mixed drills 6 in. apart, alternate grass and lucerne drills 6 in. or 12 in. apart) and their two-factor interactions were studied on yield of dry matter and proportion of lucerne. Data are reported for the total of fourteen cuts, for the annual total for three harvest years and for spring, summer and autumn cuts.

1. Data are presented indicating that both the total yield of potatoes and the proportions of the yield in size grades were a function (independent of set size) of the number of main stems per unit area for the maincrop varieties Majestic and King Edward.

1. A technique has been established for the determination of fat and fatty acid intake and excretion in weaned pigs.

The apparent and corrected digestibilities of beef tallow, H.E.F. and soyabean oil have been determined in the newly weaned pig. Determinations of the individual fatty acids in the food and faecal lipids allowed the digestibility of each acid to be calculated separately. The purest available forms of oleic, stearic and palmitic acids and their corresponding triglycerides were also used in the determination of digestibility. Although the digestibility of each fatty acid is to some extent a characteristic of the acid, the extent of absorption can also be modified by the other acids in the diet. The results.of these experiments give no clear indication of a difference between feeding fatty acids in the free form or as the triglycerides. The digestible energy values of the fats have been calculated as the product of gross energy value and corrected digestibility.

The effects of soil temperature, light intensity, soil-water tension and amount and form of N, on cation-anion relationships in Italian rye-grass were tested by growing grass in a clay loam in three experiments under glass. The grass had six levels of NO3-N or NH4-N with a uniform dressing of P, S, K, Ca and Mg; NH4-N was treated with 'NServe' to prevent nitrification. In the first experiment the grass was grown at 11°, 19-5° and 28° C, in the second in 100, 68 and 44% glasshouse ' daylight', and in the third at three soil-water tensions. Yields were greatest at 19-5° C, 100% glasshouse

1. Africander and Mashona steers, fitted with rumen cannulae, were used to study levels of various nitrogenous fractions and of dry matter in the rumen of cattle grazing on natural subtropical herbage throughout the year. Some steers received various concentrate foods in addition to veldt grazing during winter. During the summer rainy season, four steers, two of each breed, were under trial, while in the winter drought period two extra steers of each breed were added to the experiment. The eight steers were divided into four groups for the winter, one group received a protein-rich concentrate, another group received a carbohydraterich concentrate, a third group was given a mixture of the two concentrates, while the fourth group received no additional food.

1. Africander and Mashona steers, fitted with rumen cannulae, were used to study pH values and concentrations of volatile fatty acids in the rumen of cattle grazing on natural subtropical pasture through the year. Some steers received concentrated, foods in winter. During the summer, rainy season, two Africander and two Mashona steers were studied while in winter a further four steers, two of each breed, were added to the trial. The eight steers in winter were divided into four similar groups, one group received a carbohydrate-rich concentrate, another group received a protein-rich concentrate, a third group was given both concentrates, while the fourth group received no additional food.

A plot trial tested the fertilizer value of dung and urine evenly spread on Hyparrhenia veld which was very deficient in N and was also deficient, although less seriously, in P.

Data on the performance of British, Africander cross British and Brahman cross British females were examined. Of the animals mated only 56-0% of the homebred British cows produced live calves compared with 77-3 and 73-8% from Africander and Brahman cross cows respectively. Evidence was found that the low calving percentage for the.British females was connected with breeding stress, the British females being frequently unable to maintain weight if pregnancies occurred in two successive years. Under similar stress conditions crossbred-Zebu cows could thrive and breed and crossbred Brahmans in particular would normally maintain their weight.

1. A study of the effects of live-weight loss and recovery on the physical and chemical composition of 4- and 5-year-old Romney ewes is described. Six treatment groups each of eight ewes were involved. The diet consisted of chaffed lucerne alfalfa) hay. The treatment groups were:

(i) control (C);

(ii) low plane of nutrition for 21 days (LPS);

(iii) as for (ii) then changed to a high plane LPS: HP);

(iv) low plane of nutrition for 42 days (LPL)

(v) as for (iv) then changed to high plane for a short period (LPL:HPS); and

(vi) as for (iv) then changed to high plane for a long period (LPL:HPL).

Because of mortalities in the LPL:HPS and LPL:HPL groups, data on the carcasses and internal organs of the animals surviving to slaughter date in these treatments were not statistically analysed.

Bull spermatozoa were deep-frozen to −79° C. in diluents prepared with 1% lecithin and containing mixtures of sodium citrate, sodium chloride, fructose, glycine and gelatin, and revival rates measured after thawing, using scores of motility rate of progression of spermatozoa), the visual estimation of percentage of motile spermatozoa and the percentage of spermatozoa unstained by Congo-red-nigrosin. The experimental design was a one-ninth replicate of a 37 factorial. A decrease in the time taken to cool samples